Re: is nickel used in the process of making aluminum cans?

This is really a very interesting question.  It took me more than an hour 
to research it, but I learned a few things in the process.

The first point I should make is that scientists don't agree on whether 
nickel in foods really causes a problem in people sensitive to nickel 
(Veien NK. Ingested food in systemic allergic contact dermatitis. Clinics 
in Dermatology. 15(4):547-55, 1997). This same point is also noted on the 
website:  
http://allergies.about.com/health/allergies/library/weekly/aa011000a.htm

Another webpage from a fairly reputable site (Mayo Clinic Foundation)
(http://206.132.27.252/mayo/askdiet/htm/new/qd990317.htm) indicated that 
soda would not be a problem for nickel sensitive people, while "Chocolate 
and cocoa drinks, tea from dispensers" should be avoided.

I could find no evidence that aluminum cans contain any significant amount 
of nickel.

So do you have a nickel allergy *from* drinking soda? ... Probably not.  
Should you avoid soda because it would aggravate your contact dermatitis 
nickel allergy? ... Probably not.  Should you avoid certain foods if you 
have a nickel allergy? ... Maybe, but the science on this point is still 
in its infancy.  The foods to be avoided can be found on the Mayo 
Foundation webpage above.